That's not a locker, that's a whole dang transaxle. That said, MANY compact and fullsize tractors have a differential lock, often actuated by a pedal. There's a few different systems out there, but they all basically boil down to a mechanical coupling that overrides the differential action of the spider gears.

The pin that Red refers to is actually the freewheeling pin. It is pulled to disengage the wheels from the transmission, and allow the tractor to be pushed. 8 and 6 are locked together with the 11 pin. 6 is the wheel hub.

Notice how it is a solid axle(53), through the diff(67)? Huh?(that's what I though anyways!) The left side hub(54) spins on that solid axle(53), and is driven by the left side spider gears. You lock the rear by locking the left hub,54 to the axle,53 that it can spin on.

Part 45 is able to be turned, and is actually an adjustable limited slip. You can tighten it, and it locks the hub and axle with friction washers. It's not actually a locker, but can be adjusted tight enough to give almost locker action.

The parts(67, 69) I was looking at lock the solid axle to the right side spider gears.

This is what doing drafting classes, and doing journeyman machine repair work gets you....

_______________________________________________Head Mowron of the Mowercycle gang...